Various types of vending machines have been developed for dispensing a variety of articles such as books, cassettes, and food items, etc. One type of vending machine incorporates a carousel for storing and dispensing articles wherein articles are stored in bins arranged concentrically within the carousel. Typically, a positioning system is used to rotate the carousel to predetermined positions wherein an article may be retrieved through an opening in the face of the vending machine. Prior carousel type vending machines employ stepper motors and controllers which rely on encoders for determining the relative position of the carousel. While these systems are effective, they are also quite expensive.
One example of a carousel type vending machine is disclosed in U.S. Pat. No. 4,519,522. In this system the rotation of the carousel is achieved with a stepper motor and a shaft encoder wherein a complicated controller is required to advance or retard the carousel to the desired position. In U.S. Pat. No. 4,563,120, a non-carousel type of dispensing machine is disclosed wherein a grid of bins are arranged in a planar array. A carriage is moved to access articles within individual bins wherein the carriage position is also controlled by a stepper motor.
In each of the above systems, the cost and complexity of each of the respective systems is increased dramatically by the need for a stepper motor.